Electric-socket plug



.Sept 30, i924.

- w. J. SMITH LEcTRrc socxET PLUG Filed May 15, 1922 INVENTOR. M'Z'm fn?kf/ BY M Za/WA;

Patented Sept. 30, 192.41.

Aal. 1.

Les m ELECTRIC-SOCKET FLUG.

Application filed. May 15, 1922.

.To all 207mm if may concern Be it known that l, NILLiAM J. SMrri-r, acitizen of the United States.I and a resident of l/Vaterbury, county ofNew Haven, and State of Connecticut, have invented certain new anduseful lmproveinents in Electric- Socket Plugs, of which the followingis a specification.

This invention relates to electrical connectors, and more particularlyto a quick detachable plug for connecting the ends of a two-wireextension cord with the terminals of an electric socket.

One object of the invention is to provide an electric socket plug whichmay be readily pushed into the usual threaded. lamp or wall socket by adirect motion of translation, and without requiring any rotativemovement whatever.

A further object is to provide a plug which may be instantly snappedinto and removed from an electric socket.

A further ob)l ect is to provide a plug which may be securely locked inposition without the use of screw threads on said plug.

A further object is to provide an electric socket plug of the abovenature which will be simple, easy to assemble and manipulate, cheap tomanufacture, and very efficient and durable in use.

With these and otheryobjects in view, there have been illustrated Vonthe accompanying' drawings two forms in which the invention may beconveniently embodied in practice.

Fig. 1 represents a top plan view of the electric socket pluo'.

Fig. 2 is side view of the same.

Fig. 3 is a side sectional view of the plug taken along the line 3-3 ofFig. 1, looking in the direction of the arrows.

Fig. a is a side sectional view of the plug taken along the line 4 1 ofFig. 1, looking in the direction of the arrows.

Fig. 5 is a perspective view of the shellcontacting member, shown indetached position. Y

Fig. 6 is a perspective view of the connecting ring, shown in detachedposition.

Fig. 7 is a side view partly in section of one of the arms of theshell-contacting member having a modified forni of catch-lug.

In the usual form' of socket plug, it has been customary to providescrew threads upon the circumference of the plug adapted to engage inthe corresponding threads of the electric socket. This form of plug wasSerial No. 561,010.

subject to the disadvantage that the cord bccame twisted when screwingthe plug into the socket. This twisting motion not only;Y had a tendencyto produce snarls or kinks in the cord.r but oftentimes, the twist inthe cord would cause the plug to become loos cned after a short periodof use.

By means of the present invention. the above and other disadvantageshave been largely avoided.

Referring now to the drawings in which like reference numerals denotecorresponding parts throughout the several views, the numeral 1Urepresents a cylindrical supporting base having a pair of longitudinalrecesses 11 and 12 cut into opposite sides thereof. The supporting base10, which may be constructed of hard rubber or any other suitableinsulating material, preferably has its lower part provided with aknurled flange 13. lWithin the flange 13, the suppmftinn` base 10 isprovided with a pair of tubular holes 14e and 15 for lead wires 16 and17 of an extension cord`18.

A base cap 19 for the supporting base 10 is also provided for leadingthe cord 18 into the plug. This base cap 19 has an inner upstandingannular rib 2O fitting into an annular groove on the bottom flange 13 ofthe supportingbase 10. rlhe base cap 19 is prei"- erably madesubstantially semispherical in shape, but if desiredr an;T othersuitable coniiguration of the base cap may be employed. A reducedknurled section 21 is also provided upon the bottom of the base capwhich together with the knurled flange 1 3 assists in the manipulationof the device by the user.

The lea-d wire 16 after passing up through the tubular hole 15 of thesupporting base 10, is led into the longitudinal recess 12 and securedin any suitable manner, as by a binding screw QQ. to a depending arm 28of a connecting ring 211. This connecting ring` 2a has a top disksection 24, the center of which is apertured at 25. The connecting ring24 is adapted to rest upon the top of the insulating base 10 surroundinga shoulder 26 thereof.

A shell-contacting member' 27 is seated upon the top of the connectingring 24:. This member 27 is provided with a top ring section 27, similarto the disk portion 24a of the connecting ring 24. The member 27 alsohas a pair of resilient arms 28, 29, arranged at right angles to thering section 27". and depending therefrom. The depend ing arms 28 and 29are slightly tapered from top to bottom, as clearly shown in Fig. 2, andare located within the loiigitudinal recesses 11 and 12 which aresimilarly tapered. The bottom ends or' the arms 28, 29 are provided withoutwardly projecting cylindrical ringer buttons 30 and 31 prelerablyformed of insulating materia-l and secured to said arms in any suitablemanner as by riveting'.

In order to lock the plug within the shell after it has been insertedtherein. the arms 28 and 29 are provided `intermediate their f ends withoutwardly projecting` catch .lugs

32 and 33 respectively. The catch lugs and 33 are preferably providedwith free ends, and are formed bv stamping from the metal of the armsthemselves, being shaped so as to it snugly within the grooves of thescrew-threaded shell.

An alternative form of catch lug' for the resilient arms ot theshell-contacting member is disclosed in Fig. 7. In this term, there isno free end, but the lugr 34 .is merely pressed out 'from the metal inthe form of a V.

A pair oi' relatively longscrew members 35, 35 preferably made of brassor steel are providedfor detachably holding the base 1t), theshell-contacting member 27 and the connecting` rino; 24- together. Thesescrew members 35, 35, are adapted to pass through suitable holes in thebase.y the shell-contactingr member, and the connect-ing ring` and havetheir lower ends threaded to engage in screw sockets 36, 36 in the cap19. The upper ends ot the screws 3, are provided with slotted heads 37,37 whereby said screw members may be manipulated with a screw driver orother tool whenever it is desired to take the plug apart.

The wire 17 after passing' through the tubular hole 14 is led into thelongitudinal recess 11 where it is secured in any suitable manner as bymeans oi a binding screw 3S to the insulating base 10 and is spaced'from the arm 28 by a rectangular strip 37 ot insulating material. Theinner end of the screw 38 engages in a springhousing' 39 which litswithin a cylindrical recess in the top of the base 10, between thelongitudinal recesses 11 and 12. The spring-hous- 39 is provided with ahollow socket portion 40a within which is a helical spring' 41 which maybe formed of brass, steel. or any other suitable metal. and which isadapted to engage the bot-tom of a central terminal pin 42. The lower.end of the terminal pin 42 is provided with a shoulder 48 adapted nal 45of the socket member, while the. catch lugs 32 and 33 are adapted toContact with the shell terminal 46 of said socket.

In operation when it is desired to connect the plug and the socket, theoperator will grasp the. plugwith the hand and press upon the two fingerbuttons 30 and 31. The catch lugs 32 and 33 will thus be bent inwardly,permittingl the plug to be inserted as tar as it will go withoutengagement with the side threads of the socket shell 46. ritter theterminalpin 42 comes into contact with the contact-terminal 457 it willbe pushed along a slight dist-ance further in order to compress thespring member 41. The operator will then release the buttons 30 and 3l,whereupon the catch lugs 32 and will spring outwardly and engage in thegrooves of the shell socket so that the plug will be detachably lockedin position.

The distance between the lug 32 and the ring' section 27 a of theshell-contacting member should preferably be made slightly lneater thanthe distance between the lug 3:3 and said ring section, in order toallow ter the pitch et' the threads on the socket shell. so that both ofsaid catch lugs 32 and 33 will be permitted ,to seat in oppositelgrooves o'fi the threaded portion ot the shell 46.

The connecting ring- 24 and the shell-contactn;` member 27 shouldpreferably be made from bronze or brass, or if desired, any othersuitable material may be employed. It desired, the spring member 41 maybe eliminated, in which oase the terminal pin 44 and its housing wouldbe integrally joined together.

lfif'hile the wires 16 and 17 have been illustrated as passing directlyfrom the cord 18 to the binding screws 22 and 38, it will be understoodthat they may be locked in the plug' by knotting them together withinthe base cap 19, care 'being taken, of course, to see that they aresuitably insulated from one another. Y

Moreover, the supporting' base 10 and the cap 19 may be formedintegrally instead of being made` in two parts, if desired. ln thisease, the screws 35, 35 would be made much shorter, and wouldV merelyseaty in screw sockets terminating a short distance below theconnectingring' 24. struct-ion may be made at less expense, and will bemore suitabletor somepu'rposes than the form previously disclosed.

Likewise, invsome cases it may even be advantageous to omit' theconnecting ring 24 and its binding screwV 22. When this is done, thewire 16 must be made longer, and must be brought up through the entirelength of the longitudinal recess 12. and

wound about the-shoulder 26 beneath theshell-contacting member 27. t y

It will thus be seen that this invention This con provides an improvedform of unthreaded unitary plug which is adapted to be di rectly pushedinto the shell of an electric socket without any screwing motionwhatever.

It will be understood that the parts of the plug may be constructed ofany desired dimensions according to the size of the socket with which itis to be employed. lVhile the electric socket plug has been hereinillustrated in connection with lamp and wall sockets, it will beunderstood that it is also adapted to other purposes as for example,radio plugs for connecting the wires of radio outiits to their sockets.

lVhile there have been dis-closed in this specification, two forms inwhich the invention may be embodied, it is to be understood that theseforms are shown for the purpose of illustration only, and that theinvention is not to be limited lto the speciic disclosures, but may bemodified and embodied in various other forms without departing from itsspirit. In short, the invention includes all the modifications andembodiments coming within. the scope of the following claims.

Having thus fully described the invention, what is claimed as new, andfor which it is desired to secure Letters Patent, is:

l. In a socket plug for electrically connecting a pair of conductingwires to the terminals of an electric socket having a. central terminaland a screw-threaded shell, a spring-pressed pin adapted to engage saidcentral terminal, a shellcontacting member surrounding said pin, saidshell-contacting member having a flat hase and a pair of paralleldisposed resilient arms at right angles to said fiat base, each of saidresilient arms having an outwardly projecting lug for deta-chablyengaging the screw threads ofthe socket shell a connecting ring inelectrical contact with said shell-contacting member, and means forconnecting said conducting wires to said pin and said ring respectively.

2. ln a socket plug for electrically connecting a pair of conductingwires to the lcentral and threaded shell terminals of an electricsocket, a cylindrical supporting member of insulating material having apair of longitudinal wire-housing slots, a binding screw in one of saidslots and electrically connected to a central conducting plug said plugbeing adapted to contact with the central terminal of said socket` saidplug having a central recess, a springpressed pin located in saidrecess, said pin being enlarged at its lower end, the upper edges ofsaid plug being upset inwardly around said pin to lock said pin in saidrecess, and means connected to the other conA ducting wire forresiliently engaging the shell terminal of the socket.

In testimony whereof, I have affixed my signature to this specification.

WILLIAM J. sMiTH

